What is a Bill? 

A bill is an idea, written in legal language. A Member of Provincial Parliament (MPP) presents a bill to the Legislative Assembly for consideration. It may propose a new law or a change to an existing law.
In Ontario, there are several kinds of bills:  

Government Bills

A Government Bill may direct the expenditure of public money and is typically introduced to the House by a Cabinet Minister.  Government Bills reflect the policy agenda and priorities of the government party.

Private Member's Public Bills

Any Private Member, except Cabinet Ministers and the Speaker, may introduce a Private Member’s Public Bill. These bills pertain to any topic with a provincial responsibility, but cannot impose a tax or direct the spending of public funds.

Committee Bills

Committee bills are introduced by the Chairs of certain Standing Committees, and must pertain to the ministries and offices that are assigned to the committee. The proposal must receive the support of at least two-thirds of the Committee excluding the chair. 

Private Bills

Private Bills pertain to special powers or exemptions from the general law and originate with the municipality, company or individual seeking the special power or exemption. Private Bills must be introduced in the Legislative Assembly by a Private Member (not a Cabinet Minister or the Speaker).